Rigid frame building construction



Mrch 10, 1936. G. E. STREHAN 2,033,595

RIGID FRAME BUILDING CONSTRUCTION Filed July 21, 1951 I 2 Sheets-Sheet 2 INVENTOR Georg? F. Streban 40 space and usable height of the structure thereby Patented Mar. 10, 1936 UNITED, STATES PATENT OFFICE Claims.

' This invention relates to structural frames for buildings or other structures.

My invention is particularly applicable to monolithic fire-resistive structures in which a floor of concrete or other plastic material is poured in place and reinforced with steel mesh, rods or other steel shapes, and supported by con: tinuous or discontinuous floor supports or columns which are made integral with the floor. In structures to which my invention is applied, the column may be of structural steel, or of reinforced concrete, or of the composite type consisting of reinforced concrete with a metal core.

Insofar as I am aware, the design of such structures has proceeded heretofore, largely in accordance with empirical rules, and has resulted in inordinately increasing the amountand the disposition of the material used, as for example, by the introduction of unsightly and space-consuming parts such as projecting ribs, beams, girders, drop heads and column capitals;

fire-resistive construction consisting preferably of vertical and horizontal members rigidly connected to form,a rigid frame, and so proportioned and arranged as to distribute the bending and "direct stresses between the members in accordwhich the dimensions of, and the space occupied by, the individual members of the construction are minimized and the effective available floor made a maximum, without detracting from its load-supporting capacity.

' My invention further contemplates the provision of a flre-resistive-construction in which proumn capitals are eliminated, in which the fireresistive floor plate or slab is made of uniform and minimum depth or thickness throughout and provided with a fiat ceiling surface, and in which the bending stress in the floor'plate is reduced by its. rigid attachment to the floor-support or column so as to transfer some of the bending stresses on the floor plate to the support which is inherently and best suited to sustain such stresses.

- umn is used. My invention contemplates the provision of a The various objects of my invention will be clear from the description which follows, and

from the drawings, in which Fig. 1 is a typical partial floor plan of one form of my new construction.

Fig. 2 is a vertical section of the same, taken on the line 22 of Fig. l.

Fig. 3 is a perspective view of that part of a structural steel column adjacent a floor slab, showing in detail the connecting members for 10 rigidly connecting the floor slab to the column, and the means for rigidly securing the members to. the column.

Fig. 4 is a top plan view of the same.

Fig. 5 is a similar view of a modified form of the 15 same, in which a composite reinforced concrete column with a metal core is substituted for the structural steel column.

Fig. 6 is a similar view of another modified form of the same, in which a reinforced concrete col- Fig. 7 'is a front elevation of Fig. 6, partly broken away.

In that practical embodiment of my invention which I have illustrated by way .of example, I provide a suitable metallic column head indlcated generally by the numeral ii. The column head is imbedded in the floor slab I I, and serves rigidly to connect the slab to a column of any of the well known types, such as the structural steel column l2, the-composite column l3, or the reinforced concrete column I. The column head I0 is in any case so intimately and rigidly attached to the column as to form an integral rigid frame, of which the floor plate or slab II is one of the elements, and of which the vertical support or column is another element, the column head Ill forming still another and connecting element, whereby the structure can' be economically and substantially accurately designed as a rigid frame 40 structure, in distinction from a-truss, plate, or beam structure.

Included in one form of the flcor-imbedded and reinforcing column'head, I have illustrated a series ofsuitably shaped or deformed steel chanjecting ribs, beams, girders, drop heads and colnel shapes l5. It will be noted that each of the channel members l5 comprises a pair of spaced terminal portions as 11 and I8, extending radially outwardly or away from the column and diverging, said terminal portions being joined by an integral intermediate portion is. It will'be understood, however, that structural shapes other than channel shapes may be used for the column head and that said shapes may be bent in various ways to provide outwardly proiecting portions suitable to be imbedded in, and to reinforce the floor, and other portions suitable for rigid attachment to the floor column, as will be well understood by those skilled in the art, and hence as need not be illustrated nor described.

As illustrated, the terminal portions i1 and iii of the adjacent channel shapes I! are arranged back to back, and may be secured together, if desired, as by means of suitable rivets 20.

It will be understood, however, that the rivets 20 may be entirely omitted as for example, as illustrated in Figs. 5, 6 and 7. In any case, however, it is desirable that the intermediate or connecting portions I! of the channel shapes have a substantially flat inner surface so that the channel shapes may be quickly and economically, though rigidly and securely, fastened to the column, and made an integral operative part thereof.

The means for rigidLv securing the column head Iii to the column consists preferably of a suitable structural steel connection. In the form illustrated, the connection consists of a series of angle shapes 2|, 22, 22, 24.

Referring to Figs. 3 to 5 inclusive, the angle shapes or angles each have one leg 25 thereof securely and rigidly connected to the column l2 or the corresponding core 29 of the column as by means of suitable rivets, bolts or other fastening means 26, or by welding or the like, in any well known manner. The other leg 21 of each of the angles is similarly secured by means of the fastening means 28 or welding, to the portion is of each of the channel shapes. It will be noted that each of the portions it of the column head forms one side of a square and that the temiinal portions I1 and I. of the column head extend radially outwardly from the corners of the square.

I do not intend to be understood, however, as limiting my construction to the particular form of column head illustrated as it will be obvious that the projecting portions I1 and II may be arranged otherwise than at the corners of a square and may extend in directions other than radial, if desired. It will also be understood that the number of projecting portions, while illustrated as eight in number, may also be varied to provide a greater or a lesser number, as may be found convenient or desirable.

Referring now to the reinforced concrete column illustrated in Figs. 6 and 7, the angles 2|, 22, 23, and 24 are of sumcient length to be properly imbedded in the column ll throughout the greater part of their lengths but provide bearing surfaces to permit the column head to be rigidly attached thereto by the fastening means 26, 28 or by welding, as has been previously described.

In any case, the column head it serves to transmit shearing and bending stresses from the floor plate or slab l I to the vertical supports or columns according to the relative rigidity factors of these elements. As will be understood by those skilled in the art, the conditions governing the length of the portions l1 and II which are designed to be imbedded in the floor slab are first, that the shear area in the floor plate along the circumscribing circle or other surface joining the outer ends of the various terminal portions l1 and II should be sufficient to resist the total end reactions transmitted to the column, and second, that said terminal portions should be of the correct relative depth and stiffness to bend uniformly with the floor plate and to transmit that portion of the total negative moment in the rigid frame which is resisted by the column section.

My invention involves the theory that the resulting deflection and slope of the circumscribing circle or other surface Joining the ends of the terminalportions l1 and I I of the column head will equal the elastic deflection of the floor slab or plate, and the lengths of said terminal portions are designed accordingly.

It will be understood that for the support of slabs around large floor openings, where they frame directly to columns, or for the support of marginal bands of exterior wall panels, the column head is constructed of either four, six, or eight terminal portions unsymmetrically disposed around the column perimeter to fit the contour of the structure.

For example, the unsymmetrically arranged members 30, Fig. 1, may be imbedded in the wallv 3| instead of in the floor slab while the remaining terminal portions may correspond in position and arrangement to that of the portions l1 and II.

It will further be understood that the column section is designed to support both the vertical loads and the bending moments resulting from the application of load to the rigid frame.

Each column section resists the moment produced in the rigid frame by unequal adjoining spans or unbalanced loads and reduces the bending in the floor slab or plate to the same degree. In the case of exterior or marginal columns, the column section resists the unbalanced moment produced by the total live and dead loads on the adjacent panels and the slab at this location resists the, negative moment produced by this fixed condition.

The floor plate consists of a poured-in-place slab of plastic material of uniform depth or thickness throughout its entire area up to the columns. For purposes of design, the floor plate is assumed to be sub-divided into four main bands, each of one-half the respective panel width, center to center of columns and extending in both directions, as indicated by the vertical and horizontal lines of Fig. 1. The ratio of long to short side of the panel is not limited, each main band being designed for its respective load and length as an element of that rigid frame extending in the same direction as the band. Suitable reinforcement indicated generally by the numeral 32, is provided in the floor plate to resist both balanced and unbalanced loads due to unequal spans or loading. The balance I! of the panel area situated between the main bands forms a continuous floor plate extending in both directions and supported on the plurality of rigid frames.

It will be understood that the structure is poured monolithically in concrete including the pouring of the floor and of the concrete column I4 or the pouring of the concrete of the composite column I! or the fire-resistive covering of the column l2. However, the floor plate with the imbedded column head IO may be poured in place and a protective covering 34 of fire-resistive materials in pre-cast plate or block form, or plastered in place on adequate reinforcement or lath may be subsequently attached to the column section l2.

It will be understood that my new construction lends itself to substantially accurate design; that I am enabled thereby to provide a rigid, lightweight, fire-resistive structure which may be one or more stories in height, with level and flat ceiling entirely free of drop heads, column capitals, and projecting ribs and girders common to the 2,oss,soa

While I have shown and described certain speciflc embodiments of my invention, it will be understood that I do not intend to limit myself thereto but intend to claim my invention as broadly as may be permitted by the state of the prior art and the scope of the appended claims.

- I claim:

' 1. Means for providing a rigid frame fire-resistive "structure comprising a fire-resistive col-- umn, a fire-resistive floor slab of uniform depth throughout, and a column head of less depth than that of the slab, and adapted to be imbedded in the slab, said column head comprising a series of channels, each of said channels being bent to provide a pair of terminal portions in spaced relation diverging outwardly from the column, the corresponding adjacent terminal portions of the adjacent channels being arranged back to back and the remaining portion of each of saidchannels being adapted to be rigidly secured to the column to form an integral structure therewith.

' 2. A rigid frame building structure comprising a composite column of concrete having a metal core, a metallic column head adapted to, be imbedded in a floor and including a series of metallicelements having portions thereof arranged in back-to-back relation to extend outwardly from and beyond the column, the remaining portionof said elements having flat inner surfaces,

and means within the column for securing the remaining portions of said elements to the col- 3. In a fire-resistive building construction, a reinforced concrete column, a column head comprising a series of metallic membershaving end portions thereof extending outwardly from and beyond the column, and means for rigidly securing the remaining intermediate portions of said members to thecolumn comprising metallic upright angle members arranged within and imbedded in the column, and fastening means passing through the metallic member and said incolumn and having vertical rear surfaces,-and

means for rigidly securing the remaining portions of said members to the column comprising metallic upright members arranged within and imbedded in the column andrigidly secured directly to said remaining portions and comprising the sole securing and bracing means for the head.

5. In a flre resi'stive building construction, a

.flre-resistlve column including a; structural steel member, and concrete .encasing said member, a reinforced concrete floor slab ofuniform; depth throughout, a channel having a pair of out-. wardly diverging end portions; and an intermediate portion integral "with and connectingsaid end portions, the back of said channel forming three of the sides of a trapezoid and being arranged in three distinct vertical planes, the backs of the respective end portions lying in two intersecting planes and the back of the intermediate portion lying in a third plane intersecting the other two planes, said intermediate portion being secured to the structural steel member of the column, a second similarchannel arranged with the back of its end portion adjacent the back of the corresponding end portion of the adjacent similar member whereby the adjacentdiverglng portions of said members extend diagonally of the column and in the same direction, and additional similar channels similarly arranged to provide members extending outwardly from the column and sufficiently spaced to permit the complete enclosure thereof in the floor slab.

6. The combination with a column and a concrete floor slab, of means for forming a rigid end portions arranged angularly with respect toeach other and with. an integral intermediate portion connecting the end portions, the intermediate portion having a flat back surface lying in a different plane from those of either of the end portions, and means for securing said channel directly to the column to permit the transmission of bending moments from the floor slab to the column, and vice versa.

7. A column head for a rigid frame comprising a series of channels, each of said channels havinga pair of angularh' arranged end portions and having an intermediate portion integral with and joining said end portions, the adjacent channels being arranged with their corresponding end portions back to back, and the intermediate portions of said channels having flat back surfaces and arranged in the form of a polygonal prism whereby said channels are adapted to be compleiely imbedded in and intimately bonded to a face of each of the flanges of the H, member whereby one flange of each of the angles extends between the flanges of the H member and toward the corresponding flange .of the adjacent angle and in alignment with the-outer edges of the flanges'of said H member, and astructural steel channel forming part of a column head and having the central portion thereof secured to the extending flanges of said angles and having the remainder thereof angularly disposed relatively to said intermediate portion.

9. A fire-resistive rigid frame building construction comprising a floor slab of uniform thickness throughout and of reinforced plastic mate'- rial, vertical fire-resistive supports for said slab including columns each continuous through the floor slab and including vertical structural steel angles secured toand within the columns and a series of structural steel members imbedded in said slab and secured directly to and around the column by said angles and being otherwise unbraced and .i'orming rigid and direct connections between the slab and the supports, for transmitting and transferring shearing and bending stresses and strains between the slab and the supports.

10. A fire-resistive building construction comprising a reinforced floor slab of plastic material, spaced fire-resistive columns each including a structural steel member having a vertical flat face, and a series of one-piece metallic members each directly and rigidly secured to a column at said flat face and each having a plurality of extensions thereon projecting from the column in a direction wherein one end of each extension is at a greater distance from said flat face than the other end, and of less length than the distance between columns and imbedded in the slab, said slab, column and member forming, and being susceptible of being designed as a rigid frame.

11. A rigid frame building structure comprising a reinforced floor slab of plastic material, said slab being of uniform depth throughout sufficient, but not materially in excess of the depth required, to sustain the load on the floor with the requisite'factor of safety, a floor support comprising another element of the rigid frame and including an upright structural steel member, and a connection imbedded in the slab and rigidly secured to the support comprising a third element of the frame and comprising a series of structural steel shapes each having a pair of end portions arranged diagonally of the support and each having an integral connecting portion provided with a vertical face secured to the structural steel member.

12. A rigid frame building structure of fireresistive construction comprising as one of its elements, a horizontal floor plate of reinforced plastic material, fire-resistive vertical supports for the slab comprising a second element of the rigid frame, and horizontally arranged structural steel members imbedded in the slab to form an intimate bond therewith, said members each having a back surface, the central part of said surface lying in a plane of a face of the vertical support and the remainder of said surface lying in different vertical planes, means for rigidly securing the members to the supports to cause said members to form another element of the rigid frame, said elements of said rigid frame being proportioned so 'as to distribute the bending stresses and direct stresses between the horizontal and vertical elements of the structure in accordance with the theory of action of a rigid frame and in pro-. portion to the relative rigidity factors of the horizontal and vertical elements.

13. A rigid frame building structure comprising a horizontal reinforced concretemember including reinforcing rods, a vertical member, a horizontal connecting member imbedded in the concrete member independently of said rods, and means for rigidly securing the connecting member to the vertical member including an upright structural steel angle forming part of the vertical member and secured directly to the connectins member, said frame being so proportioned as to distribute stresses between the horizontal and vertical members of the structure in accordance with the theory of action of a rigid frame and in proportion to the relative rigidity factors of said members.

14. The combination with a column unit and a reinforced floor slab unit of plastic material, of a structural steel column head comprising horizontally arranged structural steel channel elements, structural steel angle elements secured in upright position to the column unit, said channel elements each including a centrally located intermediate portion provided with a vertical back surface portion and being rigidly attached to an angle element, and each of the channel elements having the remaining portions thereof angularly disposed relatively to said innermost surface portion, and diverging outwardly therefrom and extending into the floor slab and monolithically incorporated therewith to form a complete rigid frame, said elements being so proportioned as to distribute bending and direct stresses between the column and slab units and vice versa in proportion to the relative elastic rigidity of said units.

15. A rigid frame building structure of fire-resistive construction comprising a plurality of fireresistive continuous columns, each including a structural steel member having a vertical surface,

structural steel heads each having angularly spaced extensions thereon located at successive floor levels, each of said heads comprising a series of more than two similar members, each member of the head abutting against an outer surface of the'structural steel member of the column and being interposed between and adjacent two of the remaining members, separate upright angle members for rigidly connecting each of said heads directly to a column, one of the legs of each angle member being secured to the head and the other leg to said vertical surface, said angle members comprising the sole means for bracing and securing the head, a poured-in-place slab of plastic material in which each of said heads is imbedded to provide a connecting floor plate integral with and between adjacent columns, the plate being of uniform thickness throughout.

GEORGE E. STREHAN. 

